What's more, he said it could become a catalyst for one of his more outlandish proposals: the BQX connector, a waterfront streetcar to connect Brooklyn and Queens and the subway lines that criss-cross the boroughs going east and west to Manhattan.

NYEDC "I think it makes the need for the BQX even greater," he told reporters Tuesday at a jubilant press conference in Queens. "The BQX has made sense for a long time… The center of gravity for the economy in NYC is shifting [to the Brooklyn/Queens waterfront."

Theoretically, the BQX would connect the Brooklyn and Queens through a route roughly parallel to the East River that separates the boroughs from Manhattan, roughly 11 miles from Red Hook to Astoria. The Mayor originally said the project could pay for itself thanks to increasing property values along its route, but an August report said it could cost $2.7 billion, with half of that price tag coming from the federal government, AMNNY reported.

Transit advocates and other politicians have been quick to point out that the money could be put to better use, with more immediate effects.

Others said the newfound push after Amazon's announcement only gave more ammunition to its opposition, who have argued it will only increase the rate of gentrification along its route.

Still, the Friends of the BQX organization — a consortium of business owners, civic organizatons, transit advocates, and other groups near its proposed route — aren't backing down.

"Amazon's move to L.I.C. would clearly be a boon to the city's economy — but the campus would only reach its full potential with the BQX," director Jessica Schumer told the Daily News.

There's also the possibility of Amazon helping out. As part of its agreement with the city, Amazon will contribute to an infrastructure fund, which could help prepare major thoroughfares for a streetcar's inclusion.

Proposals for an environmental impact study of the streetcar are due to City officials in December, so the study can launch early next year.

Until construction is complete — the project's scheduled finish is 2029 — commuters between New York's biggest outer-boroughs will have to rely on the infamous G train, which runs along a similar route to the East, albeit with shorter trains than all other lines.